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Direct detection of dark matter?

  1. Feb 18, 2014 #1

    Chronos

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    These papers, http://arxiv.org/abs/1402.4119 and http://arxiv.org/abs/1402.2301, make a case for direct detection of dark matter. The evidence takes the form of an unidentified emission line in the x ray spectrum of galactic clusters. The line is at a frequency and intensity consistent with sterile neutrino decay.
     
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  3. Feb 18, 2014 #2
    Interesting articles, they mention more data-sets are needed to refine the uncertainties. However this looks promising. * Fingers crossed* hopefully it will pan out.
     
  4. Feb 19, 2014 #3
    I read 1402.4119. I was even going to post it. It seemed to me that is was describing the "baby-steps" toward detecting dark matter.

    The article reads to me to be self-admittedly non-definitive, but describes how we may able to detect the decay of dark matter as our abilities to measure it become more sophisticated, mentioning the future work of Astro-H as being the instrument by which we'll be able to validate the detections of current instruments.

    I think the paper also mentions that there are a number of unidentified lines. I wonder what these will turn out to be.

    One thing that I found "neat" was that the line was detected in the galaxies, but not in the "blank sky". So, clearly they're seeing something, but isn't dark matter everywhere, and hence, if decay can be seen in places where there is a lot of normal matter, wouldn't it be logical to say that the decay should also be able to be detected in the blank sky?

    Or does dark matter tend to be more dense where there is normal matter? EDIT- Nevermind, I think I found the answer: DM Halos.

    This was the first paper I learned of the "right-handed neutrino" being a DM candidate too.

    For a guy that paid more attention to economics than cosmology, the arXiv website is A LOT of fun, and most educational.
     
    Last edited: Feb 19, 2014
  5. Feb 19, 2014 #4

    marcus

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    Two of the authors of that one were also in on the "Bullet Cluster" contour mapping of DM density surrounding two merging clusters of galaxies---that made a big splash in 2006
    http://arxiv.org/abs/astro-ph/0608407
    A direct empirical proof of the existence of dark matter
    (Submitted on 19 Aug 2006)
    We present new weak lensing observations of .., a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision of two clusters, the ... stellar component and the... X-ray emitting plasma are spatially segregated. ...​

    I'm sure you remember when that paper came out. It gave people confidence that there were real clouds of DM--it the effects were due to the presence of a real substance and not due to some modification of the laws of gravity at large scale.

    By an odd coincidence my wife and I went scuba diving for a few days with one of the authors some years back and I got to talk with him a bit about X-ray astronomy.
     
  6. Feb 19, 2014 #5

    Chronos

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    This paper by Marcos Drewes; http://arxiv.org/abs/1303.6912, The Phenomenology of Right Handed Neutrinos, may be of interest to some. It provides contextual background information [especially section 6].
     
  7. Feb 25, 2014 #6

    Chronos

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    Interest from the professional community is stirring; http://arxiv.org/abs/1402.5837, 7 keV sterile neutrino dark matter from split flavor mechanism.
     
  8. Feb 25, 2014 #7

    phyzguy

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    I find the nu-MSM model to be fairly compelling. It has three right-handed sterile neutrinos, two with masses in the GeV range and one with a mass in the keV range which is presumed to be the dark matter. It seems to be consistent with all known physics with only the addition of RH neutrinos to the standard model. Logically it seems like the RH neutrinos should exist anyway, so this addition isn't much of a stretch. If these X-rays are in fact confirmation that DM is the lightest RH neutrino, that would be very exciting. Do others also find the nu-MSM a compelling model, or is there something that I'm missing?
     
  9. Feb 25, 2014 #8

    Chronos

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    The citation history of this paper; http://arxiv.org/abs/1208.4607, Dark Matter, Baryogenesis and Neutrino Oscillations from Right Handed Neutrinos, suggests the nu-MSM model is a serious contender. That it can also explain baryon asymmetry and neutrino oscillations is attractive.
     
  10. Feb 27, 2014 #9

    Chronos

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  11. Aug 6, 2014 #10
    Hi, I started a duplicate thread on this, so I add the info I posted here instead.
    It seems a paper has now been published in The Astrophysical Journal Volume 789 Number 1 here:
    "Detection of an Unidentified Emission Line in the Stacked X-Ray Spectrum of Galaxy Clusters"
    (Esra Bulbul, Maxim Markevitch, Adam Foster, Randall K. Smith, Michael Loewenstein and Scott W. Randall)
    http://iopscience.iop.org/0004-637X/789/1/13/article
    The arxiv link is (still): http://arxiv.org/abs/1402.2301 (Submitted on 10 Feb 2014 (v1), last revised 9 Jun 2014)

    Bonus material:
    Article 1: Mystery in the Perseus Cluster (NASA article)
    Article 2: Mysterious X-ray Signal Intrigues Astronomers (Chandra article)
    Article 3: Mysterious signal from the center of the Perseus Cluster unexplained by known physics (The Watchers)

    Blogs: Links to some blogs that have written about it.
     
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